This application addresses broad Challenge Areas (14) Stem Cells and (11) Regenerative Medicine and the specific Challenge Topics 14-DE-101*: Precise Reprogramming of Cells from Oral and Craniofacial Tissues and 11-DE-101: Craniofacial Tissue Regeneration. The ultimate goal of this project is to establish methods for bioengineering teeth from adult oral tissues. Tooth loss is a major health problem in the USA, experienced by up to 42% of the population in some states and disproportionately affecting minority and economically disadvantaged communities. Current state-of-the-art therapy relies on artificial titanium/ceramic dental implants that suffer from drawbacks including requiring significant surgical intervention, lack of sensitivity, susceptibility to mechanical failure and bacterial colonization, and restricted use in cases of bone deterioration or damage. The replacement of lost teeth by whole tooth regeneration is one of the ultimate goals of dental technology, and will ideally be accomplished using adult cells to avoid practical and ethical issues surrounding the use of human embryonic tissues, and problems of graft rejection. While adult mesenchymal stem cells can participate in tooth bud formation, a suitable source of adult epithelial cells has not been identified. Recent data from our and other labs indicate that activation of epithelial [unreadable]-catenin signaling is a key initiating event in embryonic tooth development, suggesting that manipulation of this pathway in adult oral epithelial cells might render them capable of participating in de novo tooth development. The objective of this proposal is to test this hypothesis, and to delineate the optimal conditions for tooth bud regeneration from [unreadable]-catenin activated embryonic and adult mouse oral cells and human cell lines. Specifically we will: (1) Determine whether oral cells from adult mice carrying an irreversible activating mutation in epithelial [unreadable]-catenin can support tooth development in vitro and in vivo;(2) Determine whether reversible oral epithelial expression of activated [unreadable]-catenin permits de novo development of teeth with normal size and shape;and (3) Determine whether cultured mouse and human adult oral epithelial cells can initiate following activation of epithelial [unreadable]-catenin signaling. These investigations have the potential to alter our approach to treating tooth loss in human patients, by using the patient's own cells to regenerate teeth that become fully integrated into the patient's tissue, circulatory system and nervous system, rather than relying on artificial synthetic implants. 7. Project Narrative Tooth loss is a major health problem in the USA, experienced by up to 42% of the population in some states and disproportionately affecting minority and economically disadvantaged communities. Dental implants are the current state-of-the-art treatment for missing teeth, but are prone to mechanical failure and infections, and are difficult to use in individuals with significant bone loss. The aim of this proposal is to develop methods for reactivating embryonic dental signaling pathways in adult oral cells for regeneration of natural teeth and their associated support tissues, including bone, blood vessels, nerves and periodontal ligament, providing improved function, sensitivity, durability and appearance.